前言
ARouter 框架主要的三个模块
image.png
先来一张图
image.png
ARouter分析
1.arouter-annotation
我们看上图，主要 compiler 和 api，其实还有一层叫做 annotation，改层里面主要定义了一些元注解，比如我们使用的 @Router()就定义在这里。
2.arouter-compiler
image.png
有三个 Processor 以及一些工具类，我们主要看 RouteProcessor，因为前面使用的 @Router 就是通过这个注解处理器来处理的。
/**
* 自动注册
*/
@AutoService(Processor.class)
/**
* 处理接收的参数 代替 getSupportedOptions() 函数
* // Options of processor
* public static final String KEY_MODULE_NAME = "moduleName";
* 接收什么参数？其实就是我们在 gradle 中配置的参数：
* javaCompileOptions {
* annotationProcessorOptions {
* arguments = [ moduleName : project.getName() ]
* }
* }
*/
@SupportedOptions(KEY_MODULE_NAME)
/**
* 指定使用 Java 的版本，代替 getSupportedSourceVersion() 函数
*/
@SupportedSourceVersion(SourceVersion.RELEASE_7)
/**
* 指定可以处理哪些注解，代替 getSupportedAnnotationTypes() 函数
* private static final String FACADE_PACKAGE = "com.alibaba.android.arouter.facade";
* public static final String ANNOTATION_TYPE_ROUTE = FACADE_PACKAGE + ".annotation.Route";
* public static final String ANNOTATION_TYPE_AUTOWIRED = FACADE_PACKAGE + ".annotation.Autowired";
* 所以其中 ANNOTATION_TYPE_ROUTE = "com.alibaba.android.arouter.facade.annotation.Route";
*/
@SupportedAnnotationTypes({ANNOTATION_TYPE_ROUTE})
public class RouteProcessor extends AbstractProcessor {
/**
* key 是 group 组,value 是 RouteMeta 集合
*/
private Map<String, Set<RouteMeta>> groupMap = new HashMap<>(); // ModuleName and routeMeta.
/**
* key 是 group 组，value 是对应 Group 类对象名字
*/
private Map<String, String> rootMap = new TreeMap<>(); // Map of root metas, used for generate class file in order.
/**
* 文件生成器 类/资源
*/
private Filer mFiler; // File util, write class file into disk.
/**
* apt 日志输出工具
*/
private Logger logger;
/**
* type(类信息)工具类
*/
private Types types;
/**
* 节点工具类(类、函数、属性都是节点)
*/
private Elements elements;
private TypeUtils typeUtils;
private String moduleName = null; // Module name, maybe its 'app' or others
private TypeMirror iProvider = null;
/**
* 初始化方法，可以从 ProcessingEnvironment 中获取一些处理器工具
*/
@Override
public synchronized void init(ProcessingEnvironment processingEnv) {
super.init(processingEnv);
mFiler = processingEnv.getFiler(); // Generate class.
types = processingEnv.getTypeUtils(); // Get type utils.
elements = processingEnv.getElementUtils(); // Get class meta.
typeUtils = new TypeUtils(types, elements);
logger = new Logger(processingEnv.getMessager()); // Package the log utils.
/**
* 这里 options.key = moduleName
* options.value = app
* 所以 moduleName = "app";
*/
// Attempt to get user configuration [moduleName]
Map<String, String> options = processingEnv.getOptions();
if (MapUtils.isNotEmpty(options)) {
moduleName = options.get(KEY_MODULE_NAME);
}
if (StringUtils.isNotEmpty(moduleName)) {
moduleName = moduleName.replaceAll("[^0-9a-zA-Z_]+", "");
logger.info("The user has configuration the module name, it was [" + moduleName + "]");
} else {
logger.error("These no module name, at 'build.gradle', like :\n" +
"apt {\n" +
" arguments {\n" +
" moduleName project.getName();\n" +
" }\n" +
"}\n");
throw new RuntimeException("ARouter::Compiler >>> No module name, for more information, look at gradle log.");
}
/**
* 这里获取的是 com.alibaba.android.arouter.facade.template.IProvider 对象
*/
iProvider = elements.getTypeElement(Consts.IPROVIDER).asType();
logger.info(">>> RouteProcessor init. <<<");
}
/**
* 注解处理器处理注解肯定会执行的方法
*
* @param annotations 使用了支持处理的注解的节点集合
* @return true 表示后续处理器不会再处理，已经处理过了
*/
@Override
public boolean process(Set<? extends TypeElement> annotations, RoundEnvironment roundEnv) {
if (CollectionUtils.isNotEmpty(annotations)) {
//获取所有被 @Route 注解的节点
Set<? extends Element> routeElements = roundEnv.getElementsAnnotatedWith(Route.class);
try {
logger.info(">>> Found routes, start... <<<");
this.parseRoutes(routeElements);
} catch (Exception e) {
logger.error(e);
}
return true;
}
return false;
}
private void parseRoutes(Set<? extends Element> routeElements) throws IOException {
if (CollectionUtils.isNotEmpty(routeElements)) {
// Perpare the type an so on.
logger.info(">>> Found routes, size is " + routeElements.size() + " <<<");
rootMap.clear();
/**
* 获取对应的节点信息
*/
TypeMirror type_Activity = elements.getTypeElement(ACTIVITY).asType();
TypeMirror type_Service = elements.getTypeElement(SERVICE).asType();
TypeMirror fragmentTm = elements.getTypeElement(FRAGMENT).asType();
TypeMirror fragmentTmV4 = elements.getTypeElement(Consts.FRAGMENT_V4).asType();
// Interface of ARouter
TypeElement type_IRouteGroup = elements.getTypeElement(IROUTE_GROUP);
TypeElement type_IProviderGroup = elements.getTypeElement(IPROVIDER_GROUP);
ClassName routeMetaCn = ClassName.get(RouteMeta.class);
ClassName routeTypeCn = ClassName.get(RouteType.class);
/*
Build input type, format as :
使用 javapoet 生成如下代码
```Map<String, Class<? extends IRouteGroup>>```
*/
ParameterizedTypeName inputMapTypeOfRoot = ParameterizedTypeName.get(
ClassName.get(Map.class),
ClassName.get(String.class),
ParameterizedTypeName.get(
ClassName.get(Class.class),
WildcardTypeName.subtypeOf(ClassName.get(type_IRouteGroup))
)
);
/*
```Map<String, RouteMeta>```
*/
ParameterizedTypeName inputMapTypeOfGroup = ParameterizedTypeName.get(
ClassName.get(Map.class),
ClassName.get(String.class),
ClassName.get(RouteMeta.class)
);
/*
构造参数名
Build input param name.
*/
ParameterSpec rootParamSpec = ParameterSpec.builder(inputMapTypeOfRoot, "routes").build();
ParameterSpec groupParamSpec = ParameterSpec.builder(inputMapTypeOfGroup, "atlas").build();
ParameterSpec providerParamSpec = ParameterSpec.builder(inputMapTypeOfGroup, "providers").build(); // Ps. its param type same as groupParamSpec!
/*
构造方法
Build method : 'loadInto'
*/
MethodSpec.Builder loadIntoMethodOfRootBuilder = MethodSpec.methodBuilder(METHOD_LOAD_INTO)
.addAnnotation(Override.class)
.addModifiers(PUBLIC)
.addParameter(rootParamSpec);
// Follow a sequence, find out metas of group first, generate java file, then statistics them as root.
for (Element element : routeElements) {
/**
* 这里 tm 获取的是被 @Router 注解了的节点的信息，比如：
* com.alibaba.android.arouter.demo.testactivity.Test1Activity
*/
TypeMirror tm = element.asType();
Route route = element.getAnnotation(Route.class);
RouteMeta routeMeta = null;
/**
* 判断注解是否在指定的类上使用，使用者可能将注解使用在错误的地方
*/
if (types.isSubtype(tm, type_Activity)) { // Activity
logger.info(">>> Found activity route: " + tm.toString() + " <<<");
/**
* 下面是 @Autowired 注释的计息，我们先不看
*/
// Get all fields annotation by @Autowired
Map<String, Integer> paramsType = new HashMap<>();
for (Element field : element.getEnclosedElements()) {
if (field.getKind().isField() && field.getAnnotation(Autowired.class) != null && !types.isSubtype(field.asType(), iProvider)) {
// It must be field, then it has annotation, but it not be provider.
Autowired paramConfig = field.getAnnotation(Autowired.class);
paramsType.put(StringUtils.isEmpty(paramConfig.name()) ? field.getSimpleName().toString() : paramConfig.name(), typeUtils.typeExchange(field));
}
}
routeMeta = new RouteMeta(route, element, RouteType.ACTIVITY, paramsType);
} else if (types.isSubtype(tm, iProvider)) { // IProvider
logger.info(">>> Found provider route: " + tm.toString() + " <<<");
routeMeta = new RouteMeta(route, element, RouteType.PROVIDER, null);
} else if (types.isSubtype(tm, type_Service)) { // Service
logger.info(">>> Found service route: " + tm.toString() + " <<<");
routeMeta = new RouteMeta(route, element, RouteType.parse(SERVICE), null);
} else if (types.isSubtype(tm, fragmentTm) || types.isSubtype(tm, fragmentTmV4)) {
logger.info(">>> Found fragment route: " + tm.toString() + " <<<");
routeMeta = new RouteMeta(route, element, RouteType.parse(FRAGMENT), null);
} else {
throw new RuntimeException("ARouter::Compiler >>> Found unsupported class type, type = [" + types.toString() + "].");
}
categories(routeMeta);
// if (StringUtils.isEmpty(moduleName)) { // Hasn't generate the module name.
// moduleName = ModuleUtils.generateModuleName(element, logger);
// }
}
/**
* 构建方法
*/
MethodSpec.Builder loadIntoMethodOfProviderBuilder = MethodSpec.methodBuilder(METHOD_LOAD_INTO)
.addAnnotation(Override.class)
.addModifiers(PUBLIC)
.addParameter(providerParamSpec);
// Start generate java source, structure is divided into upper and lower levels, used for demand initialization.
for (Map.Entry<String, Set<RouteMeta>> entry : groupMap.entrySet()) {
String groupName = entry.getKey();
MethodSpec.Builder loadIntoMethodOfGroupBuilder = MethodSpec.methodBuilder(METHOD_LOAD_INTO)
.addAnnotation(Override.class)
.addModifiers(PUBLIC)
.addParameter(groupParamSpec);
// Build group method body
/**
* 构建函数体中的内容
*/
Set<RouteMeta> groupData = entry.getValue();
for (RouteMeta routeMeta : groupData) {
switch (routeMeta.getType()) {
case PROVIDER: // Need cache provider's super class
List<? extends TypeMirror> interfaces = ((TypeElement) routeMeta.getRawType()).getInterfaces();
for (TypeMirror tm : interfaces) {
if (types.isSameType(tm, iProvider)) { // Its implements iProvider interface himself.
// This interface extend the IProvider, so it can be used for mark provider
loadIntoMethodOfProviderBuilder.addStatement(
"providers.put($S, $T.build($T." + routeMeta.getType() + ", $T.class, $S, $S, null, " + routeMeta.getPriority() + ", " + routeMeta.getExtra() + "))",
(routeMeta.getRawType()).toString(),
routeMetaCn,
routeTypeCn,
ClassName.get((TypeElement) routeMeta.getRawType()),
routeMeta.getPath(),
routeMeta.getGroup());
} else if (types.isSubtype(tm, iProvider)) {
// This interface extend the IProvider, so it can be used for mark provider
loadIntoMethodOfProviderBuilder.addStatement(
"providers.put($S, $T.build($T." + routeMeta.getType() + ", $T.class, $S, $S, null, " + routeMeta.getPriority() + ", " + routeMeta.getExtra() + "))",
tm.toString(), // So stupid, will duplicate only save class name.
routeMetaCn,
routeTypeCn,
ClassName.get((TypeElement) routeMeta.getRawType()),
routeMeta.getPath(),
routeMeta.getGroup());
}
}
break;
default:
break;
}
// Make map body for paramsType
StringBuilder mapBodyBuilder = new StringBuilder();
Map<String, Integer> paramsType = routeMeta.getParamsType();
if (MapUtils.isNotEmpty(paramsType)) {
for (Map.Entry<String, Integer> types : paramsType.entrySet()) {
mapBodyBuilder.append("put(\"").append(types.getKey()).append("\", ").append(types.getValue()).append("); ");
}
}
String mapBody = mapBodyBuilder.toString();
loadIntoMethodOfGroupBuilder.addStatement(
"atlas.put($S, $T.build($T." + routeMeta.getType() + ", $T.class, $S, $S, " + (StringUtils.isEmpty(mapBody) ? null : ("new java.util.HashMap<String, Integer>(){{" + mapBodyBuilder.toString() + "}}")) + ", " + routeMeta.getPriority() + ", " + routeMeta.getExtra() + "))",
routeMeta.getPath(),
routeMetaCn,
routeTypeCn,
ClassName.get((TypeElement) routeMeta.getRawType()),
routeMeta.getPath().toLowerCase(),
routeMeta.getGroup().toLowerCase());
}
// Generate groups
String groupFileName = NAME_OF_GROUP + groupName;
JavaFile.builder(PACKAGE_OF_GENERATE_FILE,
TypeSpec.classBuilder(groupFileName)
.addJavadoc(WARNING_TIPS)
.addSuperinterface(ClassName.get(type_IRouteGroup))
.addModifiers(PUBLIC)
.addMethod(loadIntoMethodOfGroupBuilder.build())
.build()
).build().writeTo(mFiler);
logger.info(">>> Generated group: " + groupName + "<<<");
/**
* 例子：
* groupName = test
* groupFileName = ARouter$$Group$$test
*/
rootMap.put(groupName, groupFileName);
}
if (MapUtils.isNotEmpty(rootMap)) {
// Generate root meta by group name, it must be generated before root, then I can find out the class of group.
for (Map.Entry<String, String> entry : rootMap.entrySet()) {
loadIntoMethodOfRootBuilder.addStatement("routes.put($S, $T.class)", entry.getKey(), ClassName.get(PACKAGE_OF_GENERATE_FILE, entry.getValue()));
}
}
// Wirte provider into disk
String providerMapFileName = NAME_OF_PROVIDER + SEPARATOR + moduleName;
JavaFile.builder(PACKAGE_OF_GENERATE_FILE,
TypeSpec.classBuilder(providerMapFileName)
.addJavadoc(WARNING_TIPS)
.addSuperinterface(ClassName.get(type_IProviderGroup))
.addModifiers(PUBLIC)
.addMethod(loadIntoMethodOfProviderBuilder.build())
.build()
).build().writeTo(mFiler);
logger.info(">>> Generated provider map, name is " + providerMapFileName + " <<<");
// Write root meta into disk.
String rootFileName = NAME_OF_ROOT + SEPARATOR + moduleName;
JavaFile.builder(PACKAGE_OF_GENERATE_FILE,
TypeSpec.classBuilder(rootFileName)
.addJavadoc(WARNING_TIPS)
.addSuperinterface(ClassName.get(elements.getTypeElement(ITROUTE_ROOT)))
.addModifiers(PUBLIC)
.addMethod(loadIntoMethodOfRootBuilder.build())
.build()
).build().writeTo(mFiler);
logger.info(">>> Generated root, name is " + rootFileName + " <<<");
}
}
/**
* 配置 group
* Sort metas in group.
*/
private void categories(RouteMeta routeMete) {
if (routeVerify(routeMete)) {
logger.info(">>> Start categories, group = " + routeMete.getGroup() + ", path = " + routeMete.getPath() + " <<<");
Set<RouteMeta> routeMetas = groupMap.get(routeMete.getGroup());
if (CollectionUtils.isEmpty(routeMetas)) {
Set<RouteMeta> routeMetaSet = new TreeSet<>(new Comparator<RouteMeta>() {
@Override
public int compare(RouteMeta r1, RouteMeta r2) {
try {
return r1.getPath().compareTo(r2.getPath());
} catch (NullPointerException npe) {
logger.error(npe.getMessage());
return 0;
}
}
});
//将存放了组，Route 等信息的 RouteMete 对象存放到 groupMap 集合中
routeMetaSet.add(routeMete);
groupMap.put(routeMete.getGroup(), routeMetaSet);
} else {
routeMetas.add(routeMete);
}
} else {
logger.warning(">>> Route meta verify error, group is " + routeMete.getGroup() + " <<<");
}
}
/**
* 验证合法性
* 即验证 @Route(path = "/test/abc") 这个 path 的合法性
*/
private boolean routeVerify(RouteMeta meta) {
String path = meta.getPath();
if (StringUtils.isEmpty(path) || !path.startsWith("/")) { // The path must be start with '/' and not empty!
return false;
}
/**
* 这里，其实我们使用 Route 注解的时候还可以配置组
* @Route(path = "xxxxx" group="xxxx")
* 如果group不写，默认是空字符串
*/
if (StringUtils.isEmpty(meta.getGroup())) { // Use default group(the first word in path)
try {
/**
* 这里如果 group 没有的话，我们就从 path 里面截取出组名，
* 这就是为什么我们path必须要写成 "/xxx/xxx"的格式
*/
String defaultGroup = path.substring(1, path.indexOf("/", 1));
if (StringUtils.isEmpty(defaultGroup)) {
return false;
}
//将组信息存放到 RouteMeta 对象中
meta.setGroup(defaultGroup);
return true;
} catch (Exception e) {
logger.error("Failed to extract default group! " + e.getMessage());
return false;
}
}
return true;
}
}
上面是 RouteProcessor 类的源代码，我把注释加上去了，可以自己仔细的看看。另外，如果想要了解 apt 和 javapoet 的可以去看另一篇文章。
apt 和 javapoet : https://www.jianshu.com/p/15e9a67bd1dc
现在如果我们，make app 后，可以看到如下文件。
image.png
3.arouter-api
这部分代码，我们根据使用的情况来看源码，首先我们需要调用ARouter.init(getApplication());进行初始化。
代码逐步跟踪到 LogisticsCenter 的 init() 方法。
/**
* LogisticsCenter init, load all metas in memory. Demand initialization
*/
public synchronized static void init(Context context, ThreadPoolExecutor tpe) throws HandlerException {
try {
//billy.qi modified at 2017-12-06
//load by plugin first
loadRouterMap();
//这里我修改了代码，让他直接走下面 else 中的代码
// if (registerByPlugin) {
if (false) {
} else {
Set<String> routerMap;
// 这里 routerMap 这里面的值如下面图1
// These class was generated by arouter-compiler.
routerMap = ClassUtils.getFileNameByPackageName(mContext, ROUTE_ROOT_PAKCAGE);
// 生成对应的对象并调用 loadInto() 方法，并且将Warehouse对应的字段传递进去，从而进行对其赋值
for (String className : routerMap) {
if (className.startsWith(ROUTE_ROOT_PAKCAGE + DOT + SDK_NAME + SEPARATOR + SUFFIX_ROOT)) {
// This one of root elements, load root.
((IRouteRoot) (Class.forName(className).getConstructor().newInstance())).loadInto(Warehouse.groupsIndex);
} else if (className.startsWith(ROUTE_ROOT_PAKCAGE + DOT + SDK_NAME + SEPARATOR + SUFFIX_INTERCEPTORS)) {
// Load interceptorMeta
((IInterceptorGroup) (Class.forName(className).getConstructor().newInstance())).loadInto(Warehouse.interceptorsIndex);
} else if (className.startsWith(ROUTE_ROOT_PAKCAGE + DOT + SDK_NAME + SEPARATOR + SUFFIX_PROVIDERS)) {
// Load providerIndex
((IProviderGroup) (Class.forName(className).getConstructor().newInstance())).loadInto(Warehouse.providersIndex);
}
}
}
} catch (Exception e) {
throw new HandlerException(TAG + "ARouter init logistics center exception! [" + e.getMessage() + "]");
}
}
图1
init 方法完成。
界面跳转：
ARouter.getInstance().build("/test/activity2").navigation();我们先看一下 build 方法的源码，这里说明一下，ARouter 对象的 init() 或者 build() 方法最终都会调用到 _ARouter 里面对应的方法中。
public Postcard build(String path) {
return _ARouter.getInstance().build(path);
}
protected Postcard build(String path) {
if (TextUtils.isEmpty(path)) {
throw new HandlerException(Consts.TAG + "Parameter is invalid!");
} else {
PathReplaceService pService = ARouter.getInstance().navigation(PathReplaceService.class);
if (null != pService) {
path = pService.forString(path);
}
return build(path, extractGroup(path));
}
}
这里我们点击应用内跳转后， 生成的 pService 会为 null，所以会走到 build(path,extractGroup(path));方法中。其中 extractGroup(path);方法其实就是从 path 中截取出 group 部分。
protected Postcard build(String path, String group) {
if (TextUtils.isEmpty(path) || TextUtils.isEmpty(group)) {
throw new HandlerException(Consts.TAG + "Parameter is invalid!");
} else {
PathReplaceService pService = ARouter.getInstance().navigation(PathReplaceService.class);
if (null != pService) {
path = pService.forString(path);
}
//最终 new 出一个 Postcard() 并且保存了 path 和 group
return new Postcard(path, group);
}
}
build()方法玩了以后就是 navigation() 方法了。
protected Object navigation(final Context context, final Postcard postcard, final int requestCode,
final NavigationCallback callback) {
try {
LogisticsCenter.completion(postcard);
} catch (NoRouteFoundException ex) {
if (null != callback) {//调用回调的方法
callback.onLost(postcard);
} else { // No callback for this invoke, then we use the global degrade service.
DegradeService degradeService = ARouter.getInstance().navigation(DegradeService.class);
if (null != degradeService) {
degradeService.onLost(context, postcard);
}
}
return null;
}
if (null != callback) {//调用回调方法
callback.onFound(postcard);
}
//绿色通道,跟拦截器有关
if (!postcard.isGreenChannel()) { // It must be run in async thread, maybe interceptor cost too mush time made ANR.
//...
} else {
return _navigation(context, postcard, requestCode, callback);
}
return null;
}
首先我们进入 LogisticsCenter.completion(postcard);方法。
public synchronized static void completion(Postcard postcard) {
if (null == postcard) {
throw new NoRouteFoundException(TAG + "No postcard!");
}
/**
* 先从仓库中查找 RouteMeta
* static Map<String, RouteMeta> routes = new HashMap<>();
* 其中 RouteMeta 里面存放的东西是 "/test/activity1" -> "RouteMeta 对象"
* 并且 RouteMeta 对象包含了 /test/activity1 注解所对应的类对象
*/
RouteMeta routeMeta = Warehouse.routes.get(postcard.getPath());
if (null == routeMeta) { // Maybe its does't exist, or didn't load.
/**
* 从 groupIndex 中获取
* static Map<String, Class<? extends IRouteGroup>> groupsIndex = new HashMap<>();
* 组表
*/
Class<? extends IRouteGroup> groupMeta = Warehouse.groupsIndex.get(postcard.getGroup()); // Load route meta.
if (null == groupMeta) {
throw new NoRouteFoundException(TAG + "There is no route match the path [" + postcard.getPath() + "], in group [" + postcard.getGroup() + "]");
} else {
// Load route and cache it into memory, then delete from metas.
try {
//反射创建对象
IRouteGroup iGroupInstance = groupMeta.getConstructor().newInstance();
//调用 loadInto 方法，关于这两行代码，请看图2（映射文件）
iGroupInstance.loadInto(Warehouse.routes);
//从 groupsIndex 中移除（为了节省内存）
Warehouse.groupsIndex.remove(postcard.getGroup());
} catch (Exception e) {
throw new HandlerException(TAG + "Fatal exception when loading group meta. [" + e.getMessage() + "]");
}
completion(postcard); // Reload
}
} else {
/*
将 routeMeta 中的信息复制到 postcard 信息中，因为 postcard 继承自 RouteMeta，
有些对应的字段在 RouteMeta 中
*/
postcard.setDestination(routeMeta.getDestination());
postcard.setType(routeMeta.getType());
postcard.setPriority(routeMeta.getPriority());
postcard.setExtra(routeMeta.getExtra());
Uri rawUri = postcard.getUri();
if (null != rawUri) { // Try to set params into bundle.
Map<String, String> resultMap = TextUtils.splitQueryParameters(rawUri);
Map<String, Integer> paramsType = routeMeta.getParamsType();
if (MapUtils.isNotEmpty(paramsType)) {
// Set value by its type, just for params which annotation by @Param
for (Map.Entry<String, Integer> params : paramsType.entrySet()) {
setValue(postcard,
params.getValue(),
params.getKey(),
resultMap.get(params.getKey()));
}
// Save params name which need auto inject.
postcard.getExtras().putStringArray(ARouter.AUTO_INJECT, paramsType.keySet().toArray(new String[]{}));
}
// Save raw uri
postcard.withString(ARouter.RAW_URI, rawUri.toString());
}
switch (routeMeta.getType()) {
case PROVIDER: // if the route is provider, should find its instance
// Its provider, so it must implement IProvider
Class<? extends IProvider> providerMeta = (Class<? extends IProvider>) routeMeta.getDestination();
IProvider instance = Warehouse.providers.get(providerMeta);
if (null == instance) { // There's no instance of this provider
IProvider provider;
try {
provider = providerMeta.getConstructor().newInstance();
provider.init(mContext);
Warehouse.providers.put(providerMeta, provider);
instance = provider;
} catch (Exception e) {
throw new HandlerException("Init provider failed! " + e.getMessage());
}
}
postcard.setProvider(instance);
postcard.greenChannel(); // Provider should skip all of interceptors
break;
case FRAGMENT:
postcard.greenChannel(); // Fragment needn't interceptors
default:
break;
}
}
}
图2
上述方法简单来说，就是将 postcard 对象中的信息进行了完善。回到 navigation 方法继续往下执行，在绿色通道上，不管我们是走 if 还是 else 都会调用到 _navigation() 方法。
private Object _navigation(final Context context, final Postcard postcard, final int requestCode, final NavigationCallback callback) {
final Context currentContext = null == context ? mContext : context;
switch (postcard.getType()) {
case ACTIVITY:
// Build intent
final Intent intent = new Intent(currentContext, postcard.getDestination());
intent.putExtras(postcard.getExtras());
// Set flags.
int flags = postcard.getFlags();
if (-1 != flags) {
intent.setFlags(flags);
} else if (!(currentContext instanceof Activity)) { // Non activity, need less one flag.
intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
}
// Navigation in main looper.
new Handler(Looper.getMainLooper()).post(new Runnable() {
@Override
public void run() {
if (requestCode > 0) { // Need start for result
ActivityCompat.startActivityForResult((Activity) currentContext, intent, requestCode, postcard.getOptionsBundle());
} else {
ActivityCompat.startActivity(currentContext, intent, postcard.getOptionsBundle());
}
if ((-1 != postcard.getEnterAnim() && -1 != postcard.getExitAnim()) && currentContext instanceof Activity) { // Old version.
((Activity) currentContext).overridePendingTransition(postcard.getEnterAnim(), postcard.getExitAnim());
}
if (null != callback) { // Navigation over.
callback.onArrival(postcard);
}
}
});
break;
case PROVIDER:
return postcard.getProvider();
case BOARDCAST:
case CONTENT_PROVIDER:
case FRAGMENT:
Class fragmentMeta = postcard.getDestination();
try {
Object instance = fragmentMeta.getConstructor().newInstance();
if (instance instanceof Fragment) {
((Fragment) instance).setArguments(postcard.getExtras());
} else if (instance instanceof android.support.v4.app.Fragment) {
((android.support.v4.app.Fragment) instance).setArguments(postcard.getExtras());
}
return instance;
} catch (Exception ex) {
logger.error(Consts.TAG, "Fetch fragment instance error, " + TextUtils.formatStackTrace(ex.getStackTrace()));
}
case METHOD:
case SERVICE:
default:
return null;
}
return null;
}
这部分代码看起来就简单多了，其实就是实际的页面跳转了。
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